Calcium Manganese(III) Oxides (CaMn₂O₄⋅<i>x</i> H₂O) as Biomimetic Oxygen‐Evolving Catalysts

Biomimetic and efficient: Mixed calcium manganese(III) oxides (see structure; Ca green, Mn red, O white) with elemental compositions and structures mimicking the active site of photosystem II were found to be highly active catalysts for the oxidation of water to molecular oxygen. As for PS II, the presence of Ca2+ greatly enhances the catalyst performance in comparison to the related manganese-only system Mn2O3. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.